With fast development of mobile communication and internet, a large number of mobile multimedia services have appeared, wherein some application services need multiple User Equipments (UE) to receive the same data at the same time, such as television broadcast, video conference, video on demand, online education and interactive game. Compared with general data, such mobile multimedia services have features such as large data amount and long duration. To effectively utilize mobile network resources, the 3rd Generation Partnership Project (3GPP) puts forward a Multimedia Broadcast/Multicast Service (MBMS). The MBMS refers to a point-to-multipoint service of sending data from one data source to multiple UEs, thereby sharing network resources. The MBMS can realize not only multicast and broadcast of plain text and low rate messages, but also multicast and broadcast of high rate multimedia services.
3GPP Release7 defines a Multimedia Broadcast/Multicast Service-single frequency network (MBSFN) transmission mode for Frequency Division Duplex (FDD) mode and Time Division Duplex (TDD) mode. The MBSFN transmission mode, also referred to as a single frequency network (SFN) transmission mode, is put forward and used for the transmission of MBMS services. This transmission mode is characterized that the same signal from multiple cells is required to be transmitted to a UE synchronously, and the UE will perform multipathing process to delayed signals and perform physical layer combination, thereby eliminating the interference between cells and even transforming the interference between cells into effective signals to obtain a relatively large signal-to-interference ratio, which thus helps to improve the transmission efficiency of MBMS. The SFN transmission mode in essence requires that the cells participating in the SFN adopt same scrambling code and synchronize between stations. For a Low Chip Rate (LCR) TDD system, it requires inter-station synchronization originally, and thus the cells only need to adopt the same scrambling code during the transmission of the MBMS services in the MBSFN transmission mode.
Currently, the application of MBMS transmissions based on the MBSFN mode to TDD networks refers to using one or more time slots or one independent carrier to transmit a given MBMS service on the basis of the SFN mode; and the application of MBMS transmission based on the MBSFN mode to FDD networks refers to using one independent carrier to transmit a given MBMS service on the basis of the SFN mode.
In 3GPP Release7, when a LCR TDD system transmits MBMS services with low data rate on the basis of the MBSFN mode, the LCR TDD system, taking one conventional service time slot in a LCR TDD subframe as a unit, performs MBSFN transmission of the MBMS services. As shown In FIG. 1, the LCR TDD system assigns two time slots which respectively bear two MBMS services with low data rate and the respective time slots respectively perform the MBSFN transmission to the MBMS services they bear. When the LCR TDD system transmits MBMS services with high data rate based on the MBSFN mode, it combines multiple conventional service time slots to transmit the MBMS services on the basis of the MBSFN mode. As shown in FIG. 2, the LCR TDD system assigns two continuous time slots to bear one MBMS service with high data rate, and the two continuous time slots performs one MBSFN transmission to the MBMS service they bear. The transmission mode, in which the LCR TDD system transmits MBMS services based on the MBSFN mode, requires that the minimum resource unit is one time slot, and one time slot bears one MBMS service at best, which make against resource scheduling for different MBMS services. In other words, when the transmission rate of one MBMS service cannot be accurately matched with an integral number of time slots, the MBMS service, which can be transmitted occupying less than one time slot, has to be transmitted occupying one time slot, which results in waste of bearer resources.
In the 3GPP Release7, for MBMS services with different data rates, the FDD adopts TTI as a repetitive scheduling interval, and transmits multiple MBMS services based on the MBSFN mode in a TDM mode, and the FDD adapts to MBMS services with different data rates at the scheduling frequency. That is, the TTI needs to be adjusted according to the data rates of the MBMS services to be transmitted, and the TTI is adjusted to be relatively longer when the data rate is high, and the TTI is adjusted to be relatively shorter when the data rate is low. As shown in FIG. 3, it is a schematic view illustrating performing MBSFN transmission for two MBMS services in the TDM mode with a TTI (suppose 40 ms) as a repetitive scheduling interval. This transmission mode make against the non-DRX of the UE, and as the TTI in the Release7 can be adjusted, this may lead to occupation of the same TTI resource by multiple services during the scheduling.